This invention relates to a transformer assembly including a cast insulation jacket, particularly for use in a below-grade airport navigation light system, and relates further to a method for the manufacture of the transformer assembly. Such transformers, together with associated floodlights, are sunk into airport runways and, accordingly, must be compact, completely water tight and resistant to leaching, acids and salt water in order to ensure reliability of operation.
In a transformer disclosed in U.S. Pat. No. 4,019,167, which transformer has a cast resin jacket and is usable in a airport navigation light system, an iron transformer core, around which primary and secondary coils of the transformer are wound, is encapsulated in a rubber sleeve prior to the casting of the resin jacket. The rubber sleeve serves as an additional buffer to keep thermal tensions and thermal expansions, and other effects of the iron core and coil unit, away from the cast synthetic resin jacket. To connect external electrical leads to the ends of the primary and secondary transformer windings, terminal pins are cast directly into the insulation jacket. The free outer ends of these terminal pins project into funnel-shaped depressions formed in the cast resin insulation jacket. Into the depressions are inserted rubber sockets which receive the external electrical leads and which are provided with plug sleeves mating with the terminal pins in the funnel-shaped depressions in order to operatively connect the external electrical leads to the transformer windings.
An object of the present invention is to provide an improved high-voltage, insulation-jacketed transformer of the above-described type.
Another object of the present invention is to provide such a transformer which is particularly adapted for use in the below-grade airport navigation light systems.
Another, more particular, object of the present invention is to provide such a transformer which is compact and small, watertight and resistive to salt water as well as to leaching and acids.
Another particular object of the present invention is to provide such a transformer which is easy to manufacture.